Rating of 1600mW laser and glasses


I checked various laser topic on the forum but can’t find official answer on what is the rating of the enclosure and green glasses OD?


Hi @gpt1plon;
I have the 1600mW laser for my SM1.

Information that is essential to get eyewear for this laser follows:
Type: Class 4 Blue diode laser operating on a wavelength of 445 nanometres.
The power is 1600 mW and the laser beam diameter is .5 mm. The enclosure is tinted brown and I believe I am correct in saying that it offers protection against the laser beam damaging your eyes. (please check that with one of the Snapmaker people on this forum)

I opted to buy a pair of laser eyeglasses that were very specific for this wavelength but in the end I had purchased eyewear that covered a range of wavelengths. The glasses are fitted with darker green lenses than were supplied by Snapmaker but that reflects the choice of wavelengths which are covered. The lenses are marked under EU regulations with the wavelengths covered and the optical density. My pair cover the wavelengths from 190 ~ 470 nm and they also cover 800 ~ 1700 nm. They are polycarbonate frames with solid sides and they block all laser light from the sides and through the point at the bridge of the nose so they fit really well and are light enough to wear for long periods.

The lens quality is excellent and there is no visual distortion that is sometimes evident with cheaper polycarbonate lenses. The lenses are made from CR39 optical resin and they are scratch resistant and have an optical density (OD) of 5. Looking at the link for the OD calculation website… for a back of the envelope calculation; you can see that the required minimum OD for 1.6mW laser beam is 3.2.

I bought my laser protective eyewear at an industrial laser machine and sundries supplier for around $100. I have attached an image that shows the lenses and the engraved details for which the lenses are suitable.

Hope this is helpful. :sunglasses:


Very useful and interesting thanks. Can these be worn over normal glasses though?

Hello John;
Absolutely yes. I also wear normal glasses and this type of protective eyewear is deep enough to wear over my normal spectacles without difficulty.

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good info but i think to OP wanted to know about the glasses included with the Snapmaker 2.0.

I know from other posts that the enclosure has not be tested for OD (they plan on doing this later) i have not seen anything about OD testing on the glasses, my guess would be that they have not been tested either. my recommendation is to buy good laser safety glasses (as Jepho did), and in general do not stare at running lasers.


@Atom: Hi Adam; I understood the question but approached it from a different perspective. @gpt1plon was looking for official information. It can be hard to find what you need when you are starting out with a machine (and a forum support system) that is new to you. I gave the OP just as much information as I gathered for myself when buying a second pair of protective laser glasses.

I still do not know what the official values are for the enclosure which I also have and use for SM1 when etching with the laser. Safety is key and the information I had to give when trying to buy more eyewear was considered the minimum by the service counter staff. I had to detail the startup power, beam diameter, my distance from laser while it was starting up and running and the total expected duration of my exposure in one week, in addition to the use I was trying to protect myself from. It would be useful if the enclosure sides had the wavelengths that they were designed for and the OD engraved into it. Possibly the power of the laser and beam dimensions as well. Then these questions would not need to appear.


See below answer from support:
According to our supplier, Laser transmittance is 6.5%.

The OD is 1.19. But the problem is that the testing device detects the 550nm(wavelength) light while our module’s laser beam in about 450nm.

We are asking the supplier to re-do the experiment.

I need to explain this issue clearly. The laser module face down when it is working, so the laser beam is much weaker than 1.6W laser beam. We have not measured the OCD of the dispersed laser beam as you can imagine how weak the transmitted light is.

So, yes, I agree, they would need to perform test in the correct wavelength first and then measure various reflection cases.
Worst case is obviously direct laser beam…which is, in normal condition should not happen.



@jepho i’m sorry, i meant no offense, and the information you provided was very good. i meant only to ask if you had any information on the glasses supplied with the unit as you did not mention them in your post and you seem quite knowledgeable in the area. please forgive my rudeness. :slight_smile: it seems that @gpt1plon got the information we were looking for, and thank you for sharing it.

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Hello again @gpt1plon; Regardless of wavelength, the test page (to which I linked above) still advises 3.20 as the minimum optical density required for safety for a Class 4 laser beam of 1600mW. I would be concerned… knowing that the testing device is not testing the appropriate wavelength. It is an omission that makes no sense to me in the context of user safety.

In any event an OD of 1.19 is lower than the recommended optical density and the danger in class 4 laser beams does not reside solely in a direct sight of the beam. The diffused light is also a risk to one’s sight, to say nothing of skin damage.

The method of measuring the weakest output to determine the optical density required is deeply flawed. Common sense and science would determine the very worst circumstances which are liable to occur and then protect against that.

I also cannot accept the notion that because the laser beam is face down, that the power output is much weaker. This is not true because the power of the laser beam does not alter merely because the beam is pointed in a different direction. As it stands, I do not think you are protecting your eyes adequately if you accept the idea of a weakened laser beam because of its direction and an OD of 1.19.

This is a matter which I would much prefer to see Snapmaker address with science rather than give the impression that the concerns expressed herein are of little consequence. The following link is a guide to optical density and transmission percentages.


The supplied OD of 1.19 does not reduce the strength of the laser light by c.11%. I would suggest that this is not enough protective effect. an OD of 3.2 would reduce the transmission to 1/10th of 1 percent. My own glasses at OD 5 reduce the transmission to 1000th of 1 percent. The risk factor at an OD of 1.19 is untenable in the face of these numbers.

As for the transmittance (which is not transmission) this percentage (6.5%) is a ratio of radiant light energy which contributes to the incident light falling on a body when compared with the actual light energy absorbed and transformed.

I hope this helps. :sunglasses:

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Thanks Adam; I took no offence and just supplied the facts. I am a scientist by inclination and don’t usually observe much in the way of social niceties in written communications, especially after a lifetime of writing hundreds of thousands of words for research papers. I am not particularly knowledgeable and knew absolutely nothing about CNC/3D printing and laser etching until I bought my SM1 machine.

However, I do think that it is up to the user to find out what they need to know and to ask someone who does know, where they don’t know and cannot find out. I did not know and have read a little about the subject. I appreciated your apology but I want to assure you that you did nothing wrong and have not offended me. :smiley:

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@jepho i agree with you 100% 1.19 is not strong enough. i believe that what support was trying to say is that because the laser is pointed away from the user (downward) you should never receive a full 1.6W to your eyes (because to do so you would have to have the laser pointed directly at your eyes). and once the light hits any surface it will diffuse to some degree (unless it hits a very well polished mirror?) but still when it comes to safety, play it safe, go with something that will protect you in the worst case so that you know it will protect you in every other situation. i think its also important to note that most plastics degrade with time, so the original OD will likely be higher then the the OD after a year, or 3 years. that is why i would recommend never staring at a class 4 laser, if you want to watch it do its thing, set up a camera (we all have old phones laying around right?) and watch it on a screen remotely, that is 100% safe (excluding normal eye strain caused by digital devices).

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Hi Adam; Attenuating the radiant energy by a factor of 10 (OD 1.19) or a factor of 100,000 (OD 5) is no contest. I wish there was less emphasis on how safe coherent light is when it is not directly shining at you. Class 4 lasers are able to damage eyesight by direct and diffuse light as well as damaging skin and causing fires. I would like to think that Snapmaker will take the best steps they can to address their testing and bring it into line with current standards.

I agree with you about deteriorating polycarbonates and your idea of using a phone to watch a laser is a good one. I have previously taken a picture to show how coherent and tightly focussed the laser beam is when it is on.

there is no doubting the power behind that beam of light and even though it is pointing down, I don’t believe that the beam of radiant laser energy is any the weaker for pointing down.

So which company or site did you order the glasses from? I can’t seem to find a similar spec with the price you have. All the ones I find online seem to be over $150 with the two wavelengths you listed.

Here is another thread, maybe you are interested:

Hello @jlee: I had the information on a phone but that operated only intermittently and I am using a new phone and a new operating system. I had thought that the company may have been called Lasermet and I had some dialogue with them but did not buy anything from them because of their very high prices (around $220 minimum plus heavy delivery charges). I was doing my research and contacting a huge number of companies (up to 5 per day in one particular week) and I have no information which company I eventually purchased from.

I do not see any helpful information in my bank statements. Another company I contacted was Lasercraft design and because I am no longer using iOS but Android, on my phone, I cannot access whatever information I had stored on Apple’s iPhone I had reset the phone to its factory setting before I managed to sell it to Musical Magpie. I had started my research looking for Industrial laser protective eyewear and that enquiry threw up a lot of different companies. I was just picking them off the screen at random without any clue about what was good and what was not. I am sorry that I cannot be more helpful.

Here are a few examples that won’t drain the bank account too badly.